This invention relates to a nozzle beam type metal vapor source for use in the vapor deposition of electrode materials, such as gold, during the fabrication of precision quartz-crystal resonators, or the like.
The nozzle beam source of this invention is an improvement on the nozzle beam source disclosed in U.S. Pat. No. 4,125,086 to John R. Vig et al. dated Nov. 14, 1978, and incorporated herein by reference. The nozzle beam source of the above-noted patent utilized tantalum and tungsten components; however, during the vapor depositing of gold, it has been found that gold rapidly alloys with tantalum thereby preventing the deposition of a high purity electrode material. It was also noted that gold wets hot tungsten surfaces, so that it forms a strong mechanical bond after freezing. Since the thermal expansion of gold is approximately three times that of tungsten, after a few heating cycles the gold exerts considerable hoop stresses on a tungsten container, thereby resulting in a rupture of the required source tube and crucible. It was also noted that the use of tungsten mechanical seals was unsatisfactory since, as noted above, gold wets tungsten, thus, the gold penetrated the seal. It should be understood that other metals such as copper and aluminum present the same problems as gold.